I agree With the idea to have a gp bank for each gang. That the leader accesses and members request to spend points and if they are trusted or granted permission they can buy stuff. Also gangs Should earn points every week for holding spots on skill leaderboards.
Things that should be in shop would be a 4 person gang wagon. Healing weapons. A CANNON that takes 2 members to use in a base or anywhere. Sell boost like move faster for x amount of hours or more exp.
P.s. did this on my phone dont be hating on autocorrect@Alpho